Good thinking Nigel.
This proposal echoes what I put to an agreeing crowd of archaeos and historians at Manchester Metropolitan Uni shortly after it was proposed by the Tories to link Stonehenge improvements to the road scheme. The politicians made this move for 2 reasons only - to play the budget card any way they wanted to (it is/is not within the scope of the scheme/budget), and to save face by linking the fact that the facilities were a disgrace to 'road noise' rather than decades of mismanagement (If you search the archives there is no mention of road noise until this point despite traffic chaos during the Queens Jubilee year and road works mayhem for a decade after).
Nigel's proposals also coincide with proposals virtually the same by two Salisbury District Councillors, Ian West and Colin Mills, who obviously want to see improvements to the A303, but in addition want to cancel the Countess East Theme Park centre, and build a visitor reception at Fargo North whilst removing the A344 and all the carp near the stones.
Unsurprisingly EH reaction is to pour cold water on it, and are appealing against Salisbury Council's refusal of planning permission for the monstrosity at Countess East.
We all know the cost is going to knock anything else on the head so lets get behind Salisbury Council to fight EH's appeal and stop EH living in cuckoo land where nothing gets done for another century. Following HA's success in getting a public meeting for Silbury, this appears a possible area of HA consensus and if so a quite correct vehicle to jump-on.
VBB